The present invention relates to a method of controlling tobacco flow on cigarette manufacturing machines.
On cigarette manufacturing machines, shredded tobacco is supplied pneumatically on the underside of a suction belt on to which it is sucked to form a stream of tobacco, which is eventually fed on to a paper strip traveling at the same speed as the suction belt. Once the tobacco is fed on to the paper strip, this is rolled transversely about the tobacco to form a continuous rod which is subsequently cut into pieces.
On known machines of the aforementioned type, the tobacco stream formed on the suction belt normally contains more tobacco than is actually required for forming the continuous cigarette rod. The tobacco in excess, which provides for maintaining a uniform stream on the suction belt, is removed at a shaving station by known shaving discs, the position of which in relation to the suction belt varies continuously depending on the amount of tobacco removed. More specifically, the amount of tobacco removed is measured continuously to produce a variable control signal for so adjusting the position of the shaving discs as to bring the control signal back to a predetermined minimum value.
The tobacco shaved off is normally accumulated on a conveyor by which it is fed to a measuring station some distance from the shaving discs.
The presence of the conveyor between the shaving and measuring stations involves a number of drawbacks. In addition to causing a certain amount of delay in the detection and correction of a variation in the amount of tobacco removed, the conveyor, which is essential for recycling the shaved-off tobacco, poses real problems in terms of space when it comes to machines designed to simultaneously produce two or more cigarette rods, in which case, a separate conveyor is required for each cigarette rod.